How to change admin URL - stupid question after moving hosts

[squinn]

*I have solved this since posting, Thanks.  Was reading a different tutorial, found the official one which made life easy. 
But I still have a stupid question - is it absolutely safe to delete the staging version?**

Thank you in advance.
I was using an old version of abantecart with a host I wasn't entirely happy with.  So I decided to rebuild with a new host, using the latest abantecart as a new install.
I did this on a separate 'staging' domain name so as not to mess with my live site.
After this was done, I moved all the new files to the new domain name, changed my name servers etc., so it was all under the new host

I went to the staging admin and changed where the store pointed to, which all went well, now my main domain is showing the updated abantecart as planned. Yay

The only issue is I can still only access the admin via the staging domain, not the main domain. How do I change this?
Please explain as if I am five years old, I'm not that bright. 

Thank you.

[Basara]

Hello.
You need to change your DNS record or wait for it to be updated. Try to clear DNS cache on your PC